Config file location

[Cj-Malone]

Would it be possible for you to support the xdg spec for the config location?

As in try loading in this order
$XDG_CONFIG_HOME/photobackup/config.ini
$HOME/.config/photobackup/config.ini
And then fall back to $HOME/.photobackup

Although since this is a service, maybe the config file should be stored in /etc?